Instructions

UM-0085-B09 DT80 Range User Manual Page 34
RG
Channel class
Terminal labels
Channel numbers
Applicable channel types
TCP/IP
4
MODBUS
power output
12V
5V SW
12/5V
V/I DAC
no number
PWR12V (Series 3, 4 only)
PWR5V (Series 3 only)
PWR_OUT (Series 4 only)
VDAC IDAC
(Series 4 only)
SDI-12
5D – 8D (DT80/ 85)
4D (DT81/ 82)
5 – 8
(DT80/ 85)
4 (DT81/ 82)
SDI12
channel variable
internal
1 – 1000
CV
system variable
internal
1 – 85
SV
string
internal
1 – 50
$
timer
internal
1 – 4
ST
temperature
reference
internal
no number (DT8x)
1
–
15
(CEM20)
REFT
special
internal
no number
D T DELAY CALC &name CMRR IBAT R100 VANA
VBAT VC VDD VEXT VLITH VREF VRELAY VSYS
VZERO
The "applicable channel types" column lists the different ways in which a physical input can be measured. For example,
analog channel 1 can be used to measure a voltage (specified by entering 1V), or a PT385 RTD (1PT385) or a
frequency (
1F). All of these channel types fall into the analog class, so when we talk about channel 1 we are talking
about analog channel 1.
Because each channel type is a member of one class only, there is never any confusion about which "channel 1" is being
referred to. 1C refers to digital input 1 because, from the above table, the C (counter) channel type is in the digital class.
1HSC, on the other hand, refers to counter input 1 because the HSC (high speed counter) channel type is in the counter
class. An analog channel number can be suffixed by a modifier character, which identifies the pair of terminals between
which to measure, as shown in the following table:
Modifier
Measure voltage between
none
+
and
-
*
* and #
+
+
and
#
–
- and #
#
# and AGND/EXT# (normally only used for current measurements)
Thus the channel ID 3V defines a measurement between the + and – terminals, while 3*V, 3+V and 3-V define
measurements between the *, + or – terminals (respectively) and the # terminal.
Channel Number Sequence
A channel ID that contains two channel numbers separated by two decimal points (for example, 1..3) defines a
continuous sequence of channels. If the channel IDs include terminal modifiers then the sequence will include all terminal
modifiers between that of the first channel ID and that of the second (inclusive, in the order
*, +, –, #, and only where
valid for the channel type). For example:
Sequence
is equivalent to
1..4V
1V 2V 3V 4V
1#..3#I
1#I 2#I 3#I
1+..3-R(3W)
1+R(3W) 1-R(3W) 2+R(3W) 2-R(3W) 3+R(3W) 3-R(3W)
Channel Types
The following table lists all of the channel types supported by the DT80. For each channel type, the table shows:
• the channel type mnemonic (e.g.
HV). Remember that in most cases this will be prefixed by a channel number.
Refer to Channel Numbers (P33) for details of the allowable range of channel numbers for each channel type.
• whether the channel type is "writable" (shown in the Channel Type column). Writable channel types can be
assigned a value, e.g.
2C=200 or 1CV=(2CV+3)+SIN(5CV)
• the default channel options for this channel type. These override the standard default values shown in the
channel option table. See also Channel Options (P41).
• what the channel factor does for this channel type
• the units in which data will be returned. By default, the indicated units string will be shown on the display and
appended to free format returned data, although it can be overridden if required.
• references to further details about the channel type